1. Field of the Invention
The invention relates to the field of communication. More specifically, the invention relates to communication networks.
2. Background of the Invention
The multi-protocol label switching (MPLS) protocol may be categorized as a network layer protocol of the Open Standards Institute (OSI) reference model. MPLS provides a method for generically tunneling data through networks with label switched paths (LSPs).
Routers typically internally represent each connection (whether it be an IP route, a label switched path, etc.) as an interface or set of interfaces, which is a network layer entity. Since an interface is a network layer entity, it includes various pieces of information needed for the network layer.
FIG. 1 (Prior Art) is a diagram illustrating an exemplary data structure for an interface. An interface structure 101 includes multiple fields describing the interface. An interface ID field 103 indicates a value identifying the interface. An interface type field 105 describes the type of interface (e.g., Ethernet, ATM, PoS, etc.). An IP address field 107 identifies a 32-bit IP address corresponding to the interface. A secondary IP address field 109 indicates a second 32-bit IP address for the interface. A maximum transmission unit (MTU) field 111 indicates the maximum allowable packet size to be transmitted with the interface. A bandwidth field 113 indicates the amount of bandwidth allocated to the interface. The interface structure 101 is a relatively expensive structure.
The relatively expensive interface structure consumes memory of a network element and consumes bus resources when the network element transfers interface structures to its line cards. A network element cannot maintain a relatively large number of label switched paths without hampering its performance because of the relatively expensive cost of the interface structure.